NIOBIO

introduzione

Numero atomico: 41
Gruppo: 5 or VI B
Peso atomico: 92.90638
Periodo: 5
Numero CAS: 7440-03-1

Classificazione

Metallo
Metalloide
simile a metallo
metallo alcalino
Alkali terroso
Metallo di transizione
calcogeno
alogena
Gas nobile
Lanthanoid
Actinoid
Terre rare
Platinum Metal Group
transuranici
Non ci sono isotopi stabili
Solido
Liquido
Gas
Solido (previsto)

Descrizione • Usi / Funzione

Discovered in 1801 by Hatchett in an ore sent to England more that a century before by John Winthrop the Younger, first governor of Connecticut. The metal was first prepared in 1864 by Blomstrand, who reduced the chloride by heating it ina hydrogen atmosphere. The name niobium was adopted by the International Union of Pure and Applied Chemistry in 1950 after 100 years ofcontroversy. Many leading chemical societies and government organizations refer to it by this name. Most metallurgists, leading metal societies, andall but one of the leading U.S. commercial producers, however, still refer to the metal as “columbium”. The element is found in niobite(or columbite),niobite-tantalite, pyrochlore, and euxenite. Large deposits of niobium have been found associated with carbonatites (carbon-silicate rocks), as aconstituent of pyrochlore. Extensive ore reserves are found in Canada, Brazil, Nigeria, Zaire, and in Russia. The metal can be isolated from tantalum,and prepared in several ways. It is a shiny, white, soft, and ductile metal, and takes on a bluish cast when exposed to air at room temperatures for along time. The metal starts to oxidize in air at 200°C, and when processed at even moderate temperatures must be placed in a protective atmosphere.It is used in arc-welding rods for stabilized grades of stainless steel. Thousands of pounds of niobium have been used in advance air frame systemssuch as were used in the Gemini space program. The element has superconductive properties; superconductive magnets have been made with Nb-Zrwire, which retains its superconductivity in strong magnetic fields. This type of application offers hope of direct large-scale generation of electricpower. Natural niobium is composed of only one isotope, 93Nb. Forty one other isotopes and isomers of niobium are now recognized. Niobium metal(99.9% pure) is priced at about $400/kg. 1

• "A number of transition metals (Ti, Zr, Hf, V, Nb, Ta, Mo, W) form interstitial carbides of composition MC and, in some cases, M2C. These carbides have extremely high melting points; they are very hard, and they are good electrical conductors." 2

Proprietà fisiche

Punto di fusione:3*  2477 °C = 2750.15 K = 4490.6 °F
Punto di ebollizione:3* 4744 °C = 5017.15 K = 8571.2 °F
sublimazione Point:3 
Triple Point:3 
Punto critico:3 
Densità:4  8.57 g/cm3

* - at 1 atm

configurazione elettronica

configurazione elettronica:  *[Kr] 5s1 4d4
Bloccare: d
Più alto livello di energia Occupato: 5
Elettroni di valenza: 

numeri quantici:

n = 4
ℓ = 2
m = 1
ms = +½

bonding

elettronegatività (scala Pauling):5 1.6
Electropositivity (scala Pauling): 2.4
Affinità elettronica:6 0.893 eV
ossidazione Uniti: +5,3
Funzione di lavoro:7 4.20 eV = 6.7284E-19 J

potenziale di ionizzazione   eV 8  kJ/mol  
1 6.75885    652.1
2 14.32    1381.7
potenziale di ionizzazione   eV 8  kJ/mol  
3 25.04    2416.0
4 38.3    3695.4
potenziale di ionizzazione   eV 8  kJ/mol  
5 50.55    4877.3
6 102.057    9847.0
7 125    12060.7

Termochimica

Calore specifico: 0.265 J/g°C 9 = 24.620 J/mol°C = 0.063 cal/g°C = 5.884 cal/mol°C
Conduttività termica: 53.7 (W/m)/K, 27°C 10
Calore di fusione: 26.4 kJ/mol 11 = 284.2 J/g
Calore di vaporizzazione: 682 kJ/mol 12 = 7340.7 J/g
Stato della materia Entalpia di formazione (ΔHf°)13 entropia (S°)13 Energia libera di Gibbs (ΔGf°)13
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 8.70 36.4008 0 0
(g) 173.5 725.924 44.490 186.14616 162.8 681.1552

isotopi

nuclide Massa 14 Metà vita 14 spin nucleare 14 Energia di legame
100Nb 99.914182(28) 1.5(2) s 1+ 855.16 MeV
101Nb 100.915252(20) 7.1(3) s (5/2#)+ 866.96 MeV
102Nb 101.91804(4) 1.3(2) s 1+ 875.03 MeV
103Nb 102.91914(7) 1.5(2) s (5/2+) 883.10 MeV
104Nb 103.92246(11) 4.9(3) s (1+) 881.86 MeV
105Nb 104.92394(11) 2.95(6) s (5/2+)# 889.93 MeV
106Nb 105.92797(21)# 920(40) ms 2+# 898.00 MeV
107Nb 106.93031(43)# 300(9) ms 5/2+# 896.76 MeV
108Nb 107.93484(32)# 0.193(17) s (2+) 904.83 MeV
109Nb 108.93763(54)# 190(30) ms 5/2+# 912.90 MeV
110Nb 109.94244(54)# 170(20) ms 2+# 911.66 MeV
111Nb 110.94565(54)# 80# ms [>300 ns] 5/2+# 919.73 MeV
112Nb 111.95083(75)# 60# ms [>300 ns] 2+# 918.48 MeV
113Nb 112.95470(86)# 30# ms [>300 ns] 5/2+# 926.56 MeV
81Nb 80.94903(161)# <44 ns 3/2-# 669.21 MeV
82Nb 81.94313(32)# 51(5) ms 0+ 682.87 MeV
83Nb 82.93671(34) 4.1(3) s (5/2+) 697.46 MeV
84Nb 83.93357(32)# 9.8(9) s 3+ 708.32 MeV
85Nb 84.92791(24) 20.9(7) s (9/2+) 721.98 MeV
86Nb 85.92504(9) 88(1) s (6+) 731.92 MeV
87Nb 86.92036(7) 3.75(9) min (1/2-) 744.65 MeV
88Nb 87.91833(11) 14.55(6) min (8+) 754.58 MeV
89Nb 88.913418(29) 2.03(7) h (9/2+) 767.31 MeV
90Nb 89.911265(5) 14.60(5) h 8+ 777.24 MeV
91Nb 90.906996(4) 680(130) a 9/2+ 789.97 MeV
92Nb 91.907194(3) 3.47(24)E+7 a (7)+ 797.11 MeV
93Nb 92.9063781(26) STABILE 9/2+ 806.12 MeV
94Nb 93.9072839(26) 2.03(16)E+4 a (6)+ 813.26 MeV
95Nb 94.9068358(21) 34.991(6) d 9/2+ 822.26 MeV
96Nb 95.908101(4) 23.35(5) h 6+ 828.47 MeV
97Nb 96.9080986(27) 72.1(7) min 9/2+ 836.54 MeV
98Nb 97.910328(6) 2.86(6) s 1+ 842.75 MeV
99Nb 98.911618(14) 15.0(2) s 9/2+ 849.89 MeV
I valori assegnati # non sono puramente derivati ​​da dati sperimentali, ma almeno parzialmente da tendenze sistematiche. Gira con argomenti di assegnazione deboli sono racchiusi tra parentesi. 14

Abbondanza

Terra - composti di origine: oxides 15
Terra - L'acqua di mare: 0.00001 mg/L 16
Terra -  Crosta:  20 mg/kg = 0.002% 16
Terra -  Totale:  800 ppb 17
Pianeta Mercurio) -  Totale:  610 ppb 17
Venere -  Totale:  840 ppb 17
condriti - Totale: 1.0 (relative to 106 atoms of Si) 18

Composti

Informazioni sulla sicurezza


Scheda di sicurezza - ACI Alloys, Inc.

Per maggiori informazioni

Link esterno:

fonti

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:20-4:21.
(2) - Jolly, William L. The Chemistry of the Non-Metals; Prentice-Hall: Englewood Cliffs, New Jersey, 1966; p 119.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(5) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(7) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(13) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(14) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(15) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(16) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(17) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(18) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.